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NITED STATES MILO A. RICHARDSON, OF WEST STRATFORD, CONNECTICUT.

IMPROVEMENT IN PROCESSES 0F ORNAMENTLNG CASTINGS AND PROTECTING THESURFACE OF SAME.

Specification forming part of Letters Patent No. 187,559, dated February20, 1877; application filed July 8, 1876.

To all whom it may concern:

Be it known that I, MILO A. RICHARDSON, of West Stratford, in the countyof Fairfield and State of Connecticut, have invented a new and valuableImprovement in the Process of Ornamenting and Protecting the Surface ofMetal Castings; and I do hereby declare that the following is a full,clear, and exact description of the construction and operation of thesame.

My invention relates to the ornamentation and protection of the surfaceof zinc or other metal castings; and it consists in a method or processof surfacing the same by the application of the sand-blast, andpreserving the surface so obtained from oxidation by the use of oil orsome gummy substance, in combination with a blast of steam,substantially as and for the purposes hereinafter set forth.

In the manufacture of zinc ornaments and monuments, it becomes desirableto provide the same with a neat and attractive finish. This I accomplishby applying the well-known sand-blast with steam or air. But thebeantiful finish thus obtainedis liable to be injured by exposure tomoisture, which causes decomposition of the surface of the casting, andthe formation of White oxide of zinc, that runs down and over the work,giving it an unpleasant look. To prevent this decomposition andoxidation I next apply (after the sand-blast) a fixing material,consisting of some oil or gummy substance, preferably linseed-oil, whichwill not color the metal. I then direct upon the surface of the metal ,astrong blast of steam, of at least fifty pounds pressure to the inch,and therebydrive off the excess of oil.

greatly expanded by the heat, readily enters the metal, which itprotects from moisture and consequent oxidation.

This process may be applied to other metals besides zinc.

What I claim as new, and'desire to secure Simultaneously the pores ofthe metal are opened, and the oil, which is

